Soft Sign Package

8/12/2019 Soft Sign Package

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SOFT FETAL

ULTRASOUND FINDINGS

Compiled by the Genetics Team at The Credit Valley HospitalLast updated February 2008


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Soft Fetal Ultrasound FindingsPage 2

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This document refers to the ultrasound finding of a soft sign, as compared to a clear cutstructural anomaly. There is very little information about outcomes when more thanone soft finding is seen on a fetal ultrasound. The information herein refers to isolatedsoft findings, meaning the ultrasound is otherwise unremarkable.

If the ultrasound is done at a gestation earlier than 18 weeks, a detailed fetal ultrasoundaround 18-19 weeks can be considered, since visualization of the fetus is better at latergestations, allowing for exclusion of other soft signs, and a better assessment of theoriginal finding. However, in many of the soft ultrasound findings, the natural history isthat the sign can disappear, but one cannot fully ignore the original finding.

The impact of Maternal Serum Screening (MSS) or Integrated Prenatal Screening (IPS)in estimating the risk of a true fetal chromosome anomaly in the presence of a softultrasound finding is unknown. Only for a choroid plexus cyst has the literature begunto evaluate the contribution of MSS or IPS.

It is important to remember that the risk of a significant fetal chromosome anomalyincreases with maternal age. A woman is eligible for prenatal chromosome testingwhen she is 35 or greater at the time of delivery (32 or older if twins).

Although likelihood risks have been estimated for some of the soft signs, it is importantto note that in many of the references below, the women were from high risk categories,potentially inflating the risk estimates. Also, often the number of cases reported issmall.

General References:Shipp and Benacerraf (2002). Second trimester screening for chromosomeabnormalities. Prenatal Diagnosis 22:296-307.

Smith-Bindman R. et al (2001). Second-trimester ultrasound to detect fetuses withDown syndrome. JAMA 285:1044-1055.

Van den Hof MC. et al. (2005). Fetal soft markers in obstetric ultrasound. JOGC27:592-612.


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CONTENTS

FIRST TRIMESTER SOFT SIGNS

1. Absent nasal bone2. Increased nuchal translucency

SECOND TRIMESTER SOFT SIGNS

1. Choroid plexus cyst2. Drooping choroids3. Mild ventriculomegaly4. Enlarged cistern magna5. Nasal bone hypoplasia6. Increased nuchal fold7. Echogenic cardiac focus

8. Single umbilical artery9. Pyelectasis10.Echogenic bowel11.Short femur12.Short humerus


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1. ABSENT NASAL BONE February 2008

A small nose and midface hypoplasia are well-recognized clinical features of Down

syndrome. Nasal bone ossification has been absent in a significant number of abortedfetuses with DS of varying gestations. This information provided credence to the idea ofprenatal first trimester study of the nasal bone as an additional marker for DS.

Required components for nasal bone imaging have been suggested(2)

. This includes amid-sagittal view of the fetus with the fetus occupying most of the image with clear fetalmargins.

Several studies have now been published suggesting the absence of the nasal bone inthe first trimester is associated with DS. The majority of studies emerge from Cicero etal (Nicolaides group in the UK)

(1). Six important pieces of information have emerged:

Nasal bone more likely to be absent at earlier gestations. In euploid fetuses withCRL between 45 and 54 mm, the nasal bone was absent in 4.7% cases. At CRLbetween 75 and 84 mm, the nasal bone was absent in only 1% of cases. Nasalbone assessment should be limited to first trimester fetuses with CRL> 45 mm.

Data in the studies are from a high-risk pregnancy group. Low risk population yetto be studied. Prefumo et al

(3)suggest nasal bone hypoplasia performs poorly as

a marker for DS in an unselected population. This raises the question of its useas a secondary marker rather than a primary marker.

Examining a high-risk group opting for CVS, the nasal bone was absent in 43/59(73%) trisomy 21 fetuses and only 3/603 (0.5%) euploid fetuses. If thisultrasound sign is combined with NT and biochemistry markers it is predicted the

detection of DS would increase to 93% with the same false positive rate of 5%. The same investigators found that absence of the nasal bone is also associated

with trisomy 18, trisomy 13, and monosomy X.

There appears to be an association between absent nasal bone, fetal crown-rump length, and nuchal translucency. In aneuploid pregnancies, nasal boneabsence occurs more frequently with increasing NT. When NT was at the 95

th

percentile or less the likelihood of absent nasal bone was greatest. Thelikelihood decreased as the NT increased.

There is a relationship between ethnicity and nasal bone development.

Further evaluation of nasal bone assessment performance in a low risk population must

be determined and sufficient adequately trained centres with appropriate educationaland credentialing procedures must be available before this can be used as part ofprovincial screening in Ontario. However, use of this ultrasound marker as anindependent determinant of fetal chromosome testing cannot be ignored in firsttrimester fetuses wi th CRL>45 mm.


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1. Cicero S et al. (2006) Nasal bone in first-trimester screening for trisomy 21. Am JObstet Gynecol 195:109-114

References:

2. Rosen T et al. (2007) First-trimester ultrasound assessment of the nasal bone toscreen for aneuploidy. Obstet and Gynecol. 110:2(1)399-404

3. Prefumo F et al. (2006) First-trimester nuchal translucency, nasal bones, andtrisomy 21 in selected and unselected populations. Am J Obstet Gynecol194:828-833


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2. INCREASED FETAL NUCHAL TRANSLUCENCY 11-14 weeks February 2008

Nuchal translucency (NT) is the sonographic appearance of a subcutaneous collectionof fluid behind the fetal neck. The 95th percentile measurement is 3.0 mm (which

advances slightly with gestational age), and 99

th

percentile measurement is constant at3.5 mm. NOTE: reliability of the measurement is operator dependent. Typically, thismeasurement is done as part of Integrated Prenatal Screening (IPS) or First TrimesterScreening (FTS). Screening using only the NT is to be discouraged. However, if themeasurement is significantly increased, it warrants offering counselling.

Associations

Chromosome anomalies (50% trisomy 21, 25 % trisomy 13/18, 10% Turner

syndrome, 10% other)

:An increased NT per se does not constitute a fetal abnormality.The larger the NT measurement, the greater is the risk of an adverse outcome.

congenital heart disease (>99thcentile -> overall likelihood ratio of 22.5 X populationrisk, with 1% of screened population > 99thcentile, somewhat correlates with thesize of the NT

single gene conditions, (with or without mental handicap)

other anatomic anomalies Likelihood ratio correlates with size of NT forlethal/severe anomalies,

fetal demise Likelihood ratio = 5 X but does not correlate with the size of the NT

With normal chromosomes, a normal 19 week ultrasound and echocardiogram, and withregression of the NT, there is up to a 95% chance of normal pregnancy outcome,

without major malformations.

Counselling and Management

Chromosome testing is offered, by CVS if gestation allows, or by amniocentesis. IfIPS has been started, the patient can finish the screen, but if the NT is >4 mm, theresult will be screen positive. A screen negative result does not rule out fetal trisomy18 or 21. Chromosome testing includes the offer of microarray analysis if G-bandedanalysis is normal.

:

When gestation allows, the patient can consider an ultrasound at 15 weeks, toassess viability and progression/regression of the finding, before having invasive

fetal chromosome testing by amniocentesis. Ultrasound at 19 20 weeks gestation to look for fetal structural anomalies

Echocardiogram of the heart and great vessels at 19-20 weeks if NT>3.5 mm. Ifbelow 99

thcentile, careful ultrasound, with examination of the great vessels and

heart is appropriate.

Newborn physical examination by a clinician aware of the prenatal ultrasoundfinding.


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References :

Atzel A et al., (2005). Relationship between nuchal translucency thickness andprevalence of major cardiac defects in fetuses with normal karyotype. UltrasoundObstet Gynecol. 26:154-157.

Bilardo CM. et al., (2007). Increased nuchal translucency thickness and normalkaryotype: time for parental reassurance. Ultrasound in Obstet Gynecol 30:11-18.

Haddow JE et al. (1998). Antenatal screening for Down's syndrome: where are we andwhere next? Lancet 352:336-337.

Hyett J et al. (1999). Using fetal nuchal translucency to screen for major congenitalcardiac defects at 10-14 weeks of gestation: population based cohort study. BMJ318:81-85. (See also the accompanying editorial on page 70-71)

Muller MA et al. (2004). Disappearance of enlarged nuchal translucency before 14weeks gestation: relationship with chromosomal abnormalities and pregnancy outcome.Ultrasound in Obstetrics and Gynecology 24(2):169-174

Nicolaides et al (2002). Increased fetal nuchal translucency at 11-14 weeks. PrenatalDiagnosis 22:308-315

Snijders RJM et al., (1998). UK multicentre project on assessement of risk of trisomy 21by maternal age and fetal nuchal translucency thickness at 10-14 weeks of gestation.

Souka AP et al., (2005). Increased nuchal translucency with normal karyotype. Am JObstet Gynecol 192:1005-1021.

Westin M et al., (2007) by how much does increased nuchal translucency increase therisk of adverse pregnancyoutcome in chromosomally normal fetuses? A study of 16260fetuses derived from an unselected pregnant population. Ultrasound Obstet Gynecol29:150-158.


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SECOND TRIMESTER SOFT SIGNS

1. Choroid Plexus Cyst (CPC) February 2008

As the choroid plexus develops, the covering epithelium changes and choroidal villi are

formed. The spaces between these projections (villi) may be enlarged by fluid or debristo create choroid plexus cysts.

Natural History

1-4% of all pregnancies:

:

almost all disappear by 28 weeks gestation

no long term clinical consequences for cerebral development

size, location and number do not appear to influence outcome

Association:

increased risk of trisomy 18, which becomes significant only for those > 35 at

delivery weakly associated with trisomy 21 (Down syndrome)

Counsellinga) Maternal age , prenatal screen not done amniocentesis is available based

on age, amniocentesis should be considered, - if patient is not keen onamniocentesis and if gestation permits, MSS could be undertaken, for if it is screennegative, likely the risk of trisomy 18 is diminished.

e) If there are any additional soft signs, referral for counselling and the offer of fetalchromosome is appropriate.

References:Bird LM, et al. (2002) Choroid plexus cysts in the mid-tirmester fetus. PrenatalDiagnosis 22:792-7.

Cheng PJ, et al. (2006) Association of fetal choroid plexus cysts with Trisomy 18 in apopulation previously screened by nuchal translucency thickness measurement. JSocGynecol Investig 13:280-4

Gratton et al, (1996) Choroid plexus cysts and trisomy 18: risk modification based onmaternal age and multiple marker screening. Am J Obstet Gynecol 175:1493-7.


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Ouzounian JG, et al. (2007). Isolated choroid plexus cyst or echogenic cardiac focus onprenatal ultrasound: is genetic amniocentesis indicated? Am J Obstet Gynecol.196:595.e1-e3.2. DROOPING CHOROID (dangling choroid) February 2008

The medial wall of the lateral ventricle appears to be separated from the choroid. Thenormal measurement should be less than 3 mm. The normalsize of the lateralventriclular atrial measurement is less than10 mm.

Natural History:

Unknown often resolves by the subsequent ultrasound.

Associations:

There are no clear associations with a recognized adverse clinical outcome. However,there is a small concern this might be the prelude to cerebral ventriculomegaly (whichhas a clear association with increased adverse outcomes).

Counselling

Monitor ventricular size and look for other anomalies with ultrasound at 18, 22-23weeks and 32-36 weeks. If ventriculomegaly (lateral ventricle atrial measurement of10 mm or more) is subsequently found, further counselling is warranted.

:

Amniocentesis - Since there is an association of mild cerebral ventriculomegaly withan increased risk of a chromosome anomaly, amniocentesis can be offered.

Reference:

Hertzberg, BS et al., (1994) Choroid Plexus-ventricular wall separation in fetuses withnormal-sized cerebral ventricles at sonography: postnatal outcome, Am J Radiol163:405-10.


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3. MILD CEREBRAL VENTRICULOMEGALY February 2008

Mild ventriculomegaly is defined as an axial diameter of greater than 9.9 mm, measuredacross the atrium of the posterior or anterior horn of the lateral ventricles at anygestation. Sometimes, it is described as a separation of more than 3 mm of the choroid

plexus from the medial wall of the lateral ventricle. Ventriculomegaly is distinguishedfrom hydrocephalus where there is an atrial diameter of greater than 15 mm.Hydrocephalus is not considered here.

The prevalence is about 1 in 700 low risk pregnancies.

Natural History:

Complete information of the natural history of isolated ventriculomegaly is not yetavailable, since careful long term studies have not been conducted. The size canstay the same or become smaller.

The majority of children appear to have normal development.

There is perhaps a 9% chance of cognitive disabilities, which can very in severity.This can occur even with resolution. There is a suggestion in the literature thatthose with a smaller increase in the ventricular measurement might have a smallerchance of an abnormal outocome. However, given the lack of appropriate long-term studies, it is suggested the risk of an abnormal outcome be treated withcircumspection.

Progression to hydrocephalus can occur, but the chance of this is not well known.

Progression is thought to occur in a minority of cases. There is an increased chanceof other cerebral structural anomalies which might not be detectable on an antenatalultrasound.

The chance of a fetal chromosome anomaly is estimated to be 3.8% (0-28.6%). Thecommonest is trisomy 21. It can be found in single gene disorders or sporadicconditions.

Associations:

Ventriculomegaly is weakly associated with fetal infections, most commonlycytomegalovirus (CMV) or toxoplasmosis.


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detailed ultrasound to assess for other structural anomalies or soft signs, if notalready completed

Counselling:

Additional ultrasound around 22 weeks, to look for possible progression to

hydrocephalus. If persistent, another in the third trimester is suggested.Uncommonly, an MRI can detect additional anomalies, but this is not offeredroutinely.

fetal chromosome testing

intial and convalescent maternal titres for CMV, toxoplasmosis, parvovirus

postnatal assessment for dysmorphic features and neuroimaging, if persistent

postnatal followup of developmental milestones

References:

Kelly EN, et al., (2001). Mild ventriculomegaly in the fetus, natural history, associatedfindings and outcome of isolated mild ventriculomegaly. A literature review. PrenatDiagn 21:697.

Wax JR, et al., (2004). Mild Fetal Cerebral Ventriculomegaly: diagnosis, clinicalassociations, and outcomes. Obstetrical and Gynecological Survey, 58:407.


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4. ENLARGED CISTERNA MAGNA December 2007

The cisterna magna is a fluid collection posterior to the cerebellum. It is seen as anecho-free triangle with the point oriented towards the cerebellar vermis. Prenatally, the

anterior/posterior diameter should be < 10 mm, with a normal appearing vermis, andwithout hydrocephalus. Visualization can be challenging, and must be done in thecorrect plane.

Natural History

Mega cisterna magna occurs in approximately 1/8200 pregnancies.

:

When isolated, most times the finding is benign. However, there are no largeprospective series, with adequate outcome data.

Since visualization of the posterior fossa can be limited and because thedevelopment of the posterior fossa structures is a late embryologic event, thereremains an unknown chance there could be other CNS anomalies, possibly

detectable later in gestation, such as a Dandy-Walker malformation/variant.

Associations:There might be an increased risk of a fetal chromosome anomaly, but more typically thisis when the enlarged cisterna magna is found in association with other anomalies.

When isolated, this is not an indication for fetal chromosome testing, but furtherinvestigation to look for other anomalies is indicated since some studies suggest thatit is not isolated in more than 50% of cases.

Counselling:

Another ultrasound at 21-23 weeks is suggested. If there is any uncertainty about

the fetal brain findings, an MRI would be considered. The patient can consider prenatal chromosome testing.

References:Van den Hof MC., et al. (2005) Fetal Soft markers in obstetric ultrasound. JOGC27:592-612.

Haimovici JA., et al. (1997) Clinical signficiance of isolated enlargemetn of the cisternalmagna (>10 mm) on prenatal sonography. J Ultraosund Med 16:731-734.

Long A., et al. (2006) Outcome of fetal cerebral posterior fossa anomalies. Prenat Diag

26:707-710.

Foranzo F et al. (2007) Posterior fossa malformation in fetues: a report of 56 furthercases and a review of the literature. Prenat Diagn 27:495-501.


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5. NASAL BONE HYPOPLASIA February 2008

The optimal definition for this established second trimester marker for DS seems to bemultiples of the median of nasal bone for the gestational age (1, 2, 3).

The regression curves used were based on NB of white fetuses. For race or ethnicityother thanwhite a multiplicative correction factor was used to obtain MoM (African-American,Hispanic, Asian, other).

Measurement of NB is performed as described by Sonek et al (4). This takes intoaccount the angle of measurement and placement of calipers for the length of the nasalbone.

Maternal age at delivery is independent of nasal bone MoM in both affected andunaffected fetuses.

There is a clear association between absent nasal bone and aneuploidy. Fetalchromosome testing should be offered in these cases. The association between Downsyndrome (and possibly trisomy 18) and nasal bone hypoplasia is less clear.

Amniocentesis could be offered.

1. Cusick W et al. (2007) Likelihood ratios for fetal trisomy 21 based on nasal bonelength in the second trimester: how best to define hypoplasia? Ultrasound ObstetGynecol 30:271-274.

References:

2. Odibo A et al. (2007) Defining nasal bone hypoplasia in second-trimester Downsyndrome screening: does the use of multiples of the median improve screeningefficacy? Am J Obstet and Gynecol 361 e1-e4.

3. Gianferrari et al. (2007) Absent or shortened nasal bone length and detection oDown syndrome in second trimester fetuses. Obstet and Gynecol 109(1):371-375


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6. INCREASED NUCHAL FOLD February 2008

Measurement of the thickness of the skin of the posterior neck of >6mm in secondtrimester, between 16 weeks, 0 days, and


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7. ECHOGENIC INTRACARDIAC FOCUS September 2007

The ultrasound visualizes an area (usually of the left ventricle) which is at least asechodense as bone, about 2 mm in diameter (can be up to 6 mm.) The pathologic basisis a discrete linear mineralization of the myocardial fusiform bundle of the chordae

tendinae but why it occurs is unknown.

Natural History

Found in 0.46 - 3% of pregnancies

:

Might occur more frequently in fetuses of women of Asian, African and MiddleEastern ethnicities.

No long term cardiac consequences known.

Most disappear by the third trimester, but even when it persists, normal cardiacfunction is expected.

Associations

Associated with an increased risk of a chromosome problem, typically Downsyndrome.

:

If occuring in the right ventricle, possibly the risk of a chromosome anomalymight be higher than if located in the left.

Controversy exists as to whether amniocentesis should be offered due tosignificantly different conclusions by various authors.

Counselling:

Patient can consider amniocentesis.

Further ultrasound/echocardiograms are not required.

References :Achiron et al, (1997) Obstet Gynecol 89:945-8.

Huggon C et al (2001) Ultrasound Obstet Gynecol 17:11-16.

Wax JR et al (2000) Ultrasound Obstet Gynecol 16(2):123-127.

Sotiriadis A et al (2003) Diagnostic performance of intracardiac echogenic foci for Downsyndrome: a meta-analysis. Obstet Gynecol 101:1009-1016.

Smith-Bindman R et al (2001). Second-trimester ultrasound to detect fetuses withDown syndrome. A meta-analysis. JAMA 285:1044-1055.

Goncalves, et al. (2006). Int J Gynecol Obstet 95:132-137.


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8. SINGLE UMBILICAL ARTERY September 2007

Natural History

0.3% -1% of 19 weeks gestation (total births and late pregnancy losses)

:

most have a normal outcome

Associations

19% had other ultrasound detectable anomalies (i.e. not isolated), often renal,cardiac or brain anomalies

If isolated, most newborns are normal, but there remains up to a 7% risk of otherstructural anomalies, not seen on antenatal ultrasound (heart, brain, kidney,limbs described)

small size (average weight 365 gm lower)

Possible increase in risk of preterm delivery

Slight increase in the risk of a chromosome abnormality, but usually with otherstructural anomalies

Detailed u/s at 19 weeks, including heart and great vessels

Counselling and Management:

Chance of a fetal chromosome anomaly with an isolated single umbilical artery,is low enough that fetal chromosome testing is not warranted

Follow fetal growth with ultrasound

Careful physical examination for additional anomalies after birth

References :Cantanzarite et al, (1995). Prenatal diagnosis of the two vessel cord: implications forpatient counselling and obstetric management. Ultrasound Obstet Gynecol 5:98-105.

Parill et al, (1995). The clinical significance of a single umbilical artery as an isolatedfinding on prenatal ultrasound. Obstet Gynecol 85:570-2.

Chow JS, Benson CB, Doubilet PM (1998). Frequency and nature of structuralanomalies in fetuses with single umbilical arteries. J Ultrasound Med 17:765-768.

Rinehart BK, Terrone DA, Taylor CW, Issler CM, Larmon JE, Roberts WE (2000).

Single umbilical artery is associated with an increased incidence of structural andchromosomal anomalies and growth restriction. Am J Perinat 17:229-232.

Gornall AS, Kurinczuk JJ, Konje JC (2003). Antenatal detection of a single umbilicalartery: does it matter? Prenat Diagn 23:117-123.


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9. RENAL PYELECTASIS (pelviectasis) September 2007

The AP diameter of renal pelvis is equal to or > 5 mm at gestations up to 32 weeks, 6days ORequal to or > 7 mm at gestations of 33 weeks to term. Any measurement >10mm is hydronephrosis.

occurs in about 0.7%- 3% of all pregnancies, more common in males

Natural History:

80% most resolve with no long term consequences, either in utero or in the first year

Associations

congenital hydronephrosis (diagnosed as > 10 mm after birth) risk correlates withlarger measurements

:

vesico-ureteric reflux (VUR)

more prevalent in fetus with trisomy 21 (isolated mild pyelectasis is present In about2% of babies with Down syndrome). The estimated likelihood ratio is low at 1.9, with

very wide confidence intervals.

Ultrasounds Since pelviectasis can progress, monitoring by ultrasound at 22-23weeks and after 28 weeks is suggested

Counselling and Management:

Ultrasound does not discriminate between obstructive and non-obstructiveuropathy in the second trimester

If persistent and greater than 10 mm after 28 weeks gestation, pediatricconsultation is strongly suggested after delivery.

VUR can still occur after birth, even with regression of pelviectasis

Patient can consider amniocentesis.

References :Courteville, JE et al, (1992). Fetal Pyelctasis and Down syndrome: Is geneticamniocentesis warranted? Obstet Gynecol 79:770-772.

Wickstrom EA et al. (1996). Obstet Gynecol 88:379-382.

Chudleigh T. (2001). Mild Pyelectasis. Prenat Diagn 21:936-941.

Chudleigh PM et al. (2001). The association of aneuploidy and mild fetal pyelectasis in

an unselected population: The results of a mulitcentre study. Ultrasound ObstetGynecol. 17:197-202.

Tovianinen-Salo S., et al. (2004). Fetal hydronephrosis: is there hope for consensus?Pediatr Radiol 34:519-529.


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10. ECHOGENIC BOWEL February 2008

The appearance on ultrasound of fetal bowel with an echogenicity similar to or greaterthan surrounding bone.

Found in about 0.6-2.4% of all second trimester fetuses

Natural History:

Sometimes persists, sometimes disappears

Associations

usually is a normal variant

:

swallowed bloody amniotic fluid from a placental abruption or an invasive

procedure, intraluminal inspissated meconium, or mesenteric ischemia.

Increased risks of the following have been observed, but quantitation of the riskvaries in the literature:

chromosome anomalies (trisomy 21 and others)

cystic fibrosis

congenital infection (CMV, occasionally other prenatal infections)

intrauterine growth retardation, which is associated with an increased risk ofperinatal morbidity and mortality

GI malformations

alpha Thalassemia in Oriental population

Counselling

The patient can consider amniocentesis.

:

Cystic fibrosis the risk of an affected child will vary, depending on the ethnicity,for CF is more prevalent in persons from northern Europe. Parental CF carriertesting can detect 80% of obligate carriers when parents are of northernEuropean background, but this is lower in other ethnic groups. If both parentsare carriers, definitive prenatal diagnosis is available.

Maternal initial and convalescent titres look for fetal infections.

(CMV, herpes simplex, toxoplasmosis, parvovirus B19, varicella) Detailed fetal ultrasound at 19-24 weeks to look for other structural anomalies

and for evidence of bowel obstruction/perforation, and at 30-32 weeks. If thefinding is persistent at the later ultrasound, or if there is IUGR or a GI anomaly,newborn pediatric consultation is needed.

Alpha Thalassemia screening of parents in Oriental families


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11. SHORT FEMUR LENGTH February 2008

A short femur length is defined as either a measurement below the 2.5thpercentile forgestational age or a measurement that is less than 0.9 multiples of that predicted by themeasured BPD. The relationship between bone length and head size may differ across

racial groups.

NaturalHistory

Likely normal variant of stature

:

Keep in mind ethnic differences in stature

Associations

associated with an increased risk of trisomy 21 (stronger if humeri are short too)

:

if severely shortened or presence of bowing, fractures, or reduced mineralizationmay be an initial sign of a skeletal dysplasia

occasionally an initial sign of IUGR

Management

Ultrasound - If gestation is < 18 weeks, suggest another 18-20 week ultrasound toassess bone growth. Other long bones should be assessed. Since there can belate detection of a skeletal dysplasia, another ultrasound around 23 weeks could beconsidered if there are persistent concerns on the 18-20 week ultrasound.

:

Patient can consider amniocentesis

References :Benacerraf BR. (2005). The role of the second trimester genetic sonogram in screening

for fetal Down syndrome. Semin Perinatolo 29: 386-394

Bethune M. (2007). Literature review and suggested protocol fror managing ultrasoundsoft markers for Down syndrome: Thickened nuchal fold, echogeneic bowel, shortenedfemur, shortened humerus, pyelectasis and absent or hypoplastic nasal bone.

Australasian Radiology 51:218-225.

Nyberg DA et al., (1993). Humerus and femur length shortening in detection of Down'ssyndrome. Am J Obstet Gynecol 168:534-8.

Shipp TD et al. (2001). Variation in fetal femur length with respect to maternal race. J

Ultrasound Med 20:141-144

Shipp TD et al., (2002). Prenat Dx 22:296-307

Snijders RJM et al. (2000). Femur length and trisomy 21: impact of gestational age onscreening efficiency. Ultrasound Obstet Gynecol 16:142-145


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ULTRASOUND FINDING ASSOCIATEDCHROMOSOMEABNORMALITY

OTHER POSSIBLEUNDERLYING

DIAGNOSIS(ES) ORASSOCIATED FINDINGS

IN ADDITION TO AMNIOFOR KARYOTYPE

Increased nuchaltranslucency

T21

T18

45,X

Other

CHD

Other structural

Single gene

IUD

Detailed u/s

Echo

Absen t nasal bone T21

Lowerforothers

Ethnicity important NIL

Choroid Plexus Cyst T18 NIL NIL

Drooping choroid Nil known ?Prelude toventriculomegaly

Follow-up U/S

Mild CerebralVentrriculomegaly

Any Hydrocephalus Other syndromes

Congenital infectiontitres

Follow up U/S

Enlarged cistern magna Unlikely U/S at 21-23 weeksgestation

MRI

Nasal bone hypoplasia Unclear NIL

Increased nuchal fold T21

Other

CHD

Single gene

Other

Echo

Echobright CardiacFocus

T21 NIL NIL

Single umbilical artery T21 Malformation ofkidney, heart , GI, limb

IUGR

Follow-up U/S

Renal Pyelectasis T21 obstructive uropathy

VUR

Follow up U/S

Echogenic Bowel T21,

Other

Structural GI

abnormality CF

Congenital infection

IUGR

Intrauterine death

alpha thalassemia

CF carrier testing

Congenital InfectionTitres

U/S

alpha thal screen inOrientals

Short femur/humerus T21 Skeletal Dysplasia Follow-up U/S


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Soft Sign Package